Fluid circulator with rigid diaphragm

ABSTRACT

The subject of the present invention is a fluid circulator comprising an excitable rigid diaphragm ( 1 ) which comprises at least one orifice ( 2 ), and preferably a fluid collector ( 6 ), which may or may not be secured to an upper ( 4 ) or lower ( 5 ) plate. Another subject of the invention is a diaphragm suited to the operation of this fluid circulator, a pump including this fluid circulator, a propulsion device, a nautical craft and any other use of the fluid circulator as a pump or as a mixer.

The present invention relates to a novel fluid circulator employing a rigid diaphragm, a method for operating such a circulator and a pump including such a circulator. The invention also relates to the use of such a circulator in numerous fields, particularly for biomedical, automotive, agri-foodstuff, building and public work, petrochemical and fine chemical applications. The fluid circulator according to the invention may also find applications in the manufacture of aquaria.

Numerous types of fluid circulator, particularly diaphragm pumps, are known in the prior art. For example, WO 02/09772 describes a fluid compression pump equipped with a pump head exhibiting a flexible metal diaphragm connected to a rigid compression chamber. The flexible diaphragm oscillates back and forth under the impetus of a piston driven by a linear motor. The motor drive frequency is set to a value equal or close to the mechanical resonance of the moving parts of the pump, of the mechanical springs and of the compressed fluid. This device also comprises low-pressure fluid inlet orifices equipped with intake valves, and high-pressure fluid outlet orifices.

EP 1369584 describes a membrane pump in which the membrane, which is flexible, is deformed under the action of compression rollers in such a way that the space between the membrane and the peripheral region is successively occluded and opened, thus producing a pumping action when the said space is filled with fluid.

Finally, EP 880650 describes a fluid circulator comprising a pump housing with rigid walls between which there is positioned a deformable diaphragm able to have peripheral perforations and a central orifice.

The pump housing is such that the separation of the rigid walls decreases from the intake orifice as far as the delivery orifice, and the diaphragm is excited on one of its ends, connected to the largest wall, in such a way as to a create a sequence of waves then a forced damping of the waves as they ravel along the diaphragm.

The Inventor examined the teachings of this patent EP 880650 and produced a pump corresponding to the teachings of the patent. Under the experimental conditions created by the Applicant, the operation of the pump did not correspond to the hydraulic performance that the Applicant was seeking.

The Inventor then developed a new theory about the mode of operation of the pump: according to its observations, the operation of the pump produced in accordance with the teachings of EP 880650 is not due to the deformation of the flexible diaphragm nor to the travel of waves from one end of the flexible diaphragm to the other, but rather to the force exerted by the actuator on the diaphragm.

The Inventor then concerned itself with the material of which the deformable diaphragm was made, and found that, surprisingly, the pump operated with a far better output when a rigid diaphragm equipped with an orifice was substituted for the flexible diaphragm.

The Inventor explains this phenomenon by the fact that the operation of the pump is due to a difference in the pressure of the fluid across the diaphragm and therefore to a phenomenon of pressure/depression across the diaphragm. This concept is particularly innovative and the present invention proposes a fluid circulator, which output is at least as good as that of the circulators of the prior art, which employs a means of creating a pressure difference in a fluid, the said means preferably being at least one perforated rigid diaphragm that can be excited by any means, particularly by means of an actuator.

Advantageously the fluid circulator comprises at least one plate situated near the diaphragm and remaining out of contact with the diaphragm, even when it is excited.

Advantageously, the circulator of the invention comprises two plates one on each side of the diaphragm. Each plate may be fixed to the walls of the pump circulator. The size of the plates is preferably more or less identical to or greater than that of the diaphragm. As the circulator operates, the fluid is alternately subjected to a depression and to a raised pressure according to the movement of the diaphragm.

Within the meaning of the present invention, a plate is to be understood as being any fixed rigid support, preferably moveable, which allows the fluid to be confined in a space determined by the said plate and by the diaphragm. The rigidity of the plate is preferably greater than or equal to the rigidity of the diaphragm.

According to one particular embodiment of the invention, the fluid circulator comprises several diaphragms, possibly connected to one another by spacers. A spacer is to be understood as meaning any connecting member placed between two parts, particularly two diaphragms, either to increase their strength and rigidity or to maintain a constant separation between them. Each diaphragm is made of one or more materials.

According to another embodiment, the fluid circulator according to the invention may be equipped with at least one hydraulic circuit for letting fluids in and/or out.

According to a preferred embodiment of the invention, the fluid circulator comprises at least one collector, situated near the orifice or orifices in the diaphragm. A collector within the meaning of the present invention is to be understood as being any device allowing the fluid set in motion by the diaphragm to be recovered. According to a preferred embodiment of the invention, the dimensions of the orifice are less than or equal to the dimensions of the collector, and preferably slightly less than the dimensions of the collector.

According to a preferred embodiment of the invention, the fluid is an incompressible fluid.

According to a preferred embodiment, the fluid circulator according to the invention is submersible.

The fluid circulator according to the invention has the advantage that it can be tailored in size to the application for which it is intended. It may be of an extremely small size, or of an industrial size.

The fluid circulator according to the invention can be used in very many applications, particularly as a pump or as a mixer or alternately as a propulsion device.

A fluid within the meaning of the present invention is to be understood as being any substance which deforms continuously under the action of a shear force, however small, particularly liquids, gases, powders and pastes or alternatively suspensions. The fluid used in the circulator of the invention may be incompressible or compressible; it is preferably incompressible. According to one particular embodiment of the invention, the fluid is viscous, laden and/or corrosive.

Another subject of the invention is a rigid diaphragm suited to the operation of a fluid circulator, having at least one orifice, this diaphragm being excitable particularly by means of an actuator. The rigid diaphragm according to the invention has the additional advantage over the flexible diaphragms of the prior art that it ages less quickly, allowing the period of use of a diaphragm to be lengthened and limiting the number of times it has to be replaced. The rigid diaphragm according to the invention also has the advantage of being simpler and less expensive to manufacture, and the choice of material is broad according to the envisaged applications.

A rigid diaphragm within the meaning of the present invention is to be understood as being a structure comprising two faces, one known as the upper face and the other known as the lower face, the said structure having a physical rigidity independent of its chemical structure. According to one particular embodiment of the invention, the rigid diaphragm is made up of one or more approximately planar structures, at least one of which cannot be flexed manually.

According to a preferred embodiment of the invention, the diaphragm has a Young's modulus in excess of 60 000 MPa, preferably in excess of 120 000 MPa, and very preferably in excess of 800 000 MPa.

According to another embodiment of the invention, the diaphragm is more or less non-deformable when it is subjected to the force generated by the actuator.

Advantageously, the diaphragm is made of metal, or of polymer resin, particularly polyethylene, polypropylene or of copolymers, alternatively made of carbon fibres or comprises several materials, mixed, blended or juxtaposed, or composites. All the materials, the physical properties of which make it possible to obtain a rigid diaphragm which deforms little, if at all, under the excitation which is applied to it, and which is preferably unchanging, are appropriate to the manufacture of all or part of the diaphragm according to the invention.

The diaphragm may be manufactured by moulding, by extrusion, or by any method of manufacture that is suitable according to the material or materials of which it is made.

According to one particular embodiment, the diaphragm is produced and then subjected to a surface treatment at the same time as or subsequent to its manufacture.

According to one particular embodiment of the invention, the diaphragm may comprise a diaphragm body made of a first material, and a surface layer of another material.

According to another embodiment of the invention, the diaphragm may be produced from several materials, particularly a first material situated around the orifice and at least a second material situated at the periphery of the diaphragm.

According to one particular embodiment of the invention, the diaphragm is manufactured or covered with one or more materials that can be implanted in the body of an animal, including the human body; advantageously, the diaphragm is made completely or partially from titanium or titanium alloy.

According to another particular embodiment of the invention, the diaphragm is manufactured or covered with one or more materials suitable for processing corrosive fluids.

The Applicant Company has found that the shape of the diaphragm could have an important influence on its ability not to be deformed (or to be deformed very little) under the excitation to which it is subjected.

The diaphragm according to the invention may have any shape useful to the application to which it is to be put, particularly a round, oval, rectangular, square, planar, tubular, conical, anticonical or elliptical shape.

The mass or the density of the diaphragm could also have a great influence on its ability not to be deformed as a result of the excitation to which it is subjected. The mass, density, shape and thickness of the diaphragm therefore need to be tailored to suit the desired applications for the fluid circulators including the said diaphragm.

The perforated rigid diaphragm according to the invention comprises at least one orifice. According to one particular embodiment, the rigid diaphragm of the invention has a central orifice. According to another particular embodiment of the invention, the diaphragm has at least one non-centred orifice, or a central orifice and at least one orifice situated at any point on the diaphragm, for example at the periphery.

According to one particular embodiment of the invention, the diaphragm may also be such that the orifice is equipped with a projection, on the upper face and/or on the lower face of the diaphragm, bordering the orifice over all or part of its periphery.

The rigid diaphragm according to the invention is coupled to any means suited to its excitation. According to the invention, and through the very fact that the diaphragm is rigid, it is not necessary to excite the diaphragm at a particular or given point and, in particular, it is not necessary for the excitation to be applied only to one end of the diaphragm; according to a preferred embodiment of the invention, the excitation applied to the diaphragm is such that the entire diaphragm reacts as one. Advantageously, the diaphragm is excited uniformly over its entire surface.

According to a preferred embodiment of the invention, the diaphragm is moved by an actuator producing a rectilinear, sinusoidal or otherwise movement, of variable amplitude and variable frequency. According to one embodiment of the invention, the amplitude range is from 0.1 to 30 mm, preferably 0.5 to 15 mm, very preferably from 1 to 5 mm; the frequency range is from 5 to 5000 Hz, preferably 10 to 100 Hz, very preferably from 20 to 50 Hz. The excitation force is preferably a periodic excitation force. The excitation of the diaphragm has the effect of causing it to vibrate at the chosen frequency.

In the embodiment in which the diaphragm is set in motion by an actuator, the latter is itself driven under the impetus of a source of power, for example an electric motor or an electromagnetic motor. According to one embodiment of the invention, the actuator is a mechanical means connected to a motor, and this means is capable of converting the rotary movement of the motor into a translation movement transmitted to the diaphragm by any appropriate means.

According to another embodiment of the invention, the actuator is magnetic or electromagnetic. According to a variant of the invention, the coupling between the actuator and the membrane is solely by way of electromagnetic means. In this embodiment, the diaphragm can be placed in a magnetic field created by two magnets or electromagnets situated one on each side of the said diaphragm, creating enough of a magnetic field to keep the diaphragm in the desired position and to move it and/or cause it to vibrate.

According to yet another embodiment of the invention, the means of coupling between the actuator and the diaphragm are mechanical and magnetic or electromagnetic.

According to the invention, the rigid diaphragm is not subjected either to a sequence of concentric oscillations directed towards the centre of the diaphragm or to a sequence of oscillations progressing from one end of the diaphragm to another end.

Another object of the present invention is to propose a pump including such a fluid circulator. The pump according to the invention has the additional advantage of not requiring the presence of a receptacle of the pump housing type to house the fluid circulator. The pump can be held by any means at the location where a circulation of fluid is desired. In theory, the pump according to the invention does not require the presence of a pump housing of specific shape.

Advantageously, the pump according to the invention comprises a hydraulic circuit comprising 1) a fluid inlet device, 2) the fluid circulator according to the invention, possibly placed in a pump housing delimiting the space in which the fluid flow rate is created or increased, and 3) a fluid outlet device.

Advantageously, the fluid outlet device includes at least one fluid collector, possibly secured to a plate, and situated facing or near at least one orifice in the diaphragm.

Another advantage of the pump of the invention is that it can operate without a valve. However, if, for certain applications, a valve is desired, the pump according to the invention can equally operate with a valve.

Another subject of the invention is a fluid propulsion device. According to a preferred embodiment, the device of the invention is used to propel a nautical or aquatic craft, preferably a jet ski.

Another subject of the invention is the use of the pump, of the fluid circulator or of the diaphragm according to the invention for medical or biomedical applications. In this field, the rigid diaphragm of the invention has additional advantages over the devices of the prior art. Specifically, it is able to get around the disadvantage that very few flexible materials are permitted for biomedical applications, it is able to offer a wider choice of possible materials and it makes it possible to avoid the disadvantages inherent in the lack of reliability and durability seen in a hospital environment with flexible parts regularly set in motion or kept in motion for a long time. Finally, surface treatments of the equipment rendered necessary for the medical applications are made easier because of the fact that the diaphragm is rigid rather than flexible.

Another subject of the invention is a method for operating the fluid circulator, in which a rigid diaphragm equipped with at least one orifice is immersed in a fluid and actuated in such a way as to create a pressure difference in the fluid across the diaphragm, and the use of such a diaphragm to create a variation or a differential in pressure within a fluid.

According to a particular embodiment, the diaphragm situated in a horizontal plane is moved along a vertical plane, preferably perpendicular to the horizontal plane of the diaphragm. According to a preferred embodiment, the movement of the diaphragm under the action of the excitation is a movement that allows it to move from a low position to a high position, and vice versa, whatever the nature of the movement. According to one particular embodiment, this movement may describe a circular path.

The invention will be better understood from reading the description which follows, which gives a non-limiting illustration of the invention and is to be read in conjunction with FIGS. 1 to 3.

FIG. 1 a depicts a perforated diaphragm according to the invention, viewed face-on.

FIG. 1 b depicts an elliptical diaphragm according to the invention, viewed in section.

FIGS. 2 a, 2 b and 2 c are sectioned views of a fluid circulator according to the invention made up of a circular diaphragm, of an upper plate secured to a collector and of a lower plate.

FIG. 3 depicts a perspective view of the diaphragm of the invention, with an upper plate and a lower plate.

The particular embodiment depicted in FIG. 1 relates to a circular diaphragm 1 made of aluminium 134 mm in diameter and 3 mm thick, perforated at its centre with an orifice 2, 20 mm in diameter.

The orifices 2 formed in the diaphragm are not necessarily round. Their size is dependent on the size of the diaphragm.

In the particular embodiment of the invention in FIG. 2 a, the diaphragm is placed in a reservoir or a pump housing 3 in a horizontal plane between two plates 4, 5. The plate 4 comprises a collector 6. The fluid circulator according to the invention further comprises an actuator 7, it being understood that the movement of the diaphragm 1 may be brought about by any appropriate means, particularly electrical, electromechanical or magnetic means. According to a preferred embodiment, the actuator 7 is driven by an electric motor and converts the rotary movement into a reciprocating movement in a vertical plane which is applied to a stirrup 8 connected to the diaphragm 1 or bearing the diaphragm 1. The reservoir is filled with fluid by a fluid inlet device 9.

According to one particular embodiment of the invention, the fluid circulator is immersed in fluid. Advantageously, the edges of the reservoir 3 containing the fluid are not contiguous with the periphery of the diaphragm and are preferably a large distance away from the diaphragm 1. The plates 4, 5 may or may not be fixed to the edges of the reservoir. According to the embodiment in FIG. 2 a, when the diaphragm 1 is excited, it vibrates in a vertical plane.

Vibration, within the meaning of the present invention, is to be understood as being the variation with respect to time of the position of the diaphragm, in which variation the said position is alternately above and below a mean position. A first movement of the diaphragm 1 towards the upper plate 4 compresses the fluid on one side of the diaphragm, that situated between the diaphragm 1 and the upper plate 4, and creates a depression on the other side of the diaphragm 1. This movement therefore has the effect of creating a variation in the pressure of the fluid across the diaphragm 1.

This variation in pressure causes fluid to move from the high-pressure region to the low-pressure region, through the orifices 2 in the diaphragm and also, to a lesser extent, around the periphery of the diaphragm. As it passes through the orifice 2 in the diaphragm, particularly where the orifice is a central orifice, the speed of the fluid accelerates, probably through an effect similar to the venturi effect.

The respective positions of the upper 4 and lower 5 plates and their distance from the diaphragm 1 are adjusted to optimize the flow rate obtained. According to a preferred embodiment of the invention, the fluid flow obtained is recovered in full or in part by at least one collector 6, possibly secured to a plate, which is situated facing or near the orifice 2 or the orifices 2 in the diaphragm.

In the embodiment of FIG. 2 b, the circulator has no reservoir. The plates 4 and 5 are secured to one another by any appropriate means and surround the diaphragm 1 with a device 4′. The fluid inlet 9 is formed in the device 4′. The fluid outlet is via the collector(s) 6 formed in the device 4′ facing or near the orifice or orifices 2. The diaphragm 1 is still borne by stirrups 8 actuated by the actuator 7.

In the embodiment of FIG. 2 c, the circulator is actuated by an electromagnetic means comprising coils 10 and magnets 11 secured to or inserted in the diaphragm 1, preferably at the periphery of the diaphragm 1. In another embodiment of the invention, the coils are on the diaphragm 1 and the magnet or magnets are near and not in contact with the coils.

FIG. 3 depicts a perspective view of a circular diaphragm (1) according to the invention, situated between an upper plate (4) and a lower plate (5), the diaphragm being actuated by any means and vibrating between the two plates. In this embodiment, the upper plate (5) is secured to a fluid collector (6). 

1. Fluid circulator comprising at least one excitable rigid diaphragm (1) which comprises at least one orifice (2).
 2. Fluid circulator according to claim 1, wherein that the said diaphragm (1) comprises a central orifice (2).
 3. Fluid circulator according to claim 1, wherein that the said diaphragm (1) comprises at least one non-centred orifice (2).
 4. Fluid circulator according to claim 1, wherein the said diaphragm (1) is manufactured or covered with one or more materials that can be implanted in the body of an animal, preferably titanium.
 5. Fluid circulator according to claim 1, wherein the said diaphragm (1) is manufactured or covered with one or more materials suitable for processing corrosive fluids, preferably stainless steel.
 6. Fluid circulator according to claim 1 wherein it comprises several diaphragms (1), possibly connected to one another by spacers.
 7. Fluid circulator according to claim 1, furthermore comprising at least one plate (4, 5) situated near the diaphragm and remaining out of contact with the diaphragm (1), even when it is excited.
 8. Fluid circulator according to claim 1, comprising two plates (4, 5) situated one on each side of the perforated rigid diaphragm, it being possible for the said two plates (4, 5) either to be secured or not to be secured to one another.
 9. Fluid circulator according to claim 1, further comprising at least one hydraulic circuit for letting fluids in and/or out.
 10. Fluid circulator according to claim 1, further comprising at least one fluid collector (6), situated near the orifice or orifices (2) in the diaphragm (1).
 11. Fluid circulator according to claim 1, wherein the said fluid is incompressible.
 12. Fluid circulator according to claim 1, further comprising an actuator (7), driven by a source of energy, preferably an electric motor or an electromagnetic motor, which sets the diaphragm (1) in motion.
 13. Fluid circulator according to claim 1, wherein the said fluid circulator is submersible.
 14. Fluid circulator according to claim 1, wherein the dimensions of the orifice (2) are less than or equal to the dimensions of the collector (6).
 15. Fluid circulator according to claim 1, wherein the orifice (2) is equipped with a projection, on the upper face and/or on the lower face of the diaphragm, bordering the said orifice over all or part of its periphery.
 16. Diaphragm suited to the operation of a fluid circulator according to claim
 1. 17. Pump comprising a hydraulic circuit equipped with at least one fluid inlet orifice, with at least one fluid circulator according to claim 1, the said fluid circulator being placed in a pump housing delimiting the space in which the fluid flow rate is created or increased, and a fluid outlet device, equipped with at least one collector (6) of the said fluid.
 18. Pump according to claim 17, characterized in that a space is formed between the exterior periphery of the diaphragm (1) and the pump housing (3).
 19. Pump according to claim 17, characterized in that it comprises no valve.
 20. Medical device, characterized in that it comprises a fluid circulator according to any one of claims 1 to
 15. 21. Fluid propulsion device, characterized in that it comprises a fluid circulator according to any one of claims 1 to
 15. 22. Nautical or aquatic craft, characterized in that it includes a propulsion device according to claim
 21. 23. Use of a fluid circulator according to any one of claims 1 to 15 for circulating biological, corrosive, viscous and/or laden fluids.
 24. Use of a fluid circulator according to any one of claims 1 to 15 as a pump or as a mixer. 